Grease Refiner Operator: Tends kettle that refines grease according to specifications: Moves lever to admit grease into kettle and opens valve to admit steam into grease to control boiling. Draws off sample of grease and inspects it for clarity. Starts pump to add required amounts of acid to kettle and boils grease with acid until grease reaches specified clarity. Closes steam valve and allows water and impurities to settle to bottom of kettle. Opens valve to drain off water and impurities. Closes drain valve, opens steam valve, and starts pump to fill kettle with water. Boils mixture for specified amount of time to wash out acid and remaining impurities. Opens drain valve to drain off water and impurities. Pumps grease to storage tanks.